Transfer of ß-lactam and tetracycline antibiotics from spiked bovine milk to Dambo-type cheese, whey, and whey powder.

The aim of this study was to investigate the transfer of residues of five ß-lactam antibiotics (ampicillin, penicillin G, cloxacillin, dicloxacillin and cephalexin) and two tetracyclines (tetracycline and oxytetracycline) in the processing of cheese and whey powder, evaluating the effect of the processes and the final concentration in each product generated. Raw milk was fortified at two concentration levels with the seven antibiotics. The first concentration level (C1) was chosen according to the maximum residue limit (MRL) of each antibiotic (ampicillin and penicillin G: 4 µg kg-1; cloxacillin and dicloxacillin: 30 µg kg-1; cephalexin, tetracycline and oxytetracycline: 100 µg kg-1). The second concentration level (C2) was spiked as follows according to each antibiotic: 0.5 MRL (cloxacillin, dicloxacillin, cephalexin), 0.1 MRL (tetracycline and oxytetracycline) and 3 MRL (ampicillin and penicillin G). The antibiotics were analyzed by LC-MS/MS. No ampicillin or penicillin G residues were found in cheese or whey powder, although they were detected in whey at concentrations similar to those added to raw milk. Cephalexin was mostly distributed in whey between 82% and 96%, being the antibiotic that presented the highest concentration in whey powder (784 ± 98 µg kg-1) when milk was spiked at the MRL. The whey distribution of cloxacillin and dicloxacillin ranged from 57% to 59% for cloxacillin and from 46% to 48% for dicloxacillin, and both concentrated in whey powder. Tetracyclines were the antibiotics that concentrated in cheese, with retentions between 75% and 80% for oxytetracycline and between 83% and 87% for tetracycline. The distribution of antibiotics in the dissimilar stages of the cheese and whey powder production processes, as well as their concentration in the final products, depend on each type of antibiotic. Knowledge of the transfer of antibiotic residues during the process and final disposal is an input for the risk assessment of their consumption.

La planta industrializadora de Leche Pil La Paz

En este capitulo se definio el problema que tiene la planta industrializadora de leche PIL La Paz: "La falta de materia prima para elaborar sus productos", asimismo se determino que a nivel departamental la empresa enfrenta una competencia por parte de un creciente numero de establecimientos que se dedican a la elaboracion de productos lacteos y que han incursionado en el mercado potencial de Pil La Paz. Tambien se observa que la empresa no cuenta con una herramienta de planificacion para lograr incrementar su participacion en el mercado y liderizar en el mismo. A partir del problema principal se definio el objetivo general: "Incrementar el bien de consumo final, leche fluida pasteurizada elaborada por la planta industrializadora de leche Pil La Paz para aumentar el porcentaje de participacion de la empresa en el mercado de la ciudad de La Paz y satisfacer la demanda existente y asi elevar las utilidades de la empresa". Luego de definir el objetivo se procedio a determinar las condiciones de cumplimiento del objetivo, y la construccion de perfiles estadisticos, donde se indica la fuente e informacion necesaria para la elaboracion del proyecto.